Presence information refers to contact information concerning a entity, referred to as a presentity, to which other entities can subscribe in a presence server database. For example, if a presentity is a mobile telecommunications subscriber, presence information that is stored for the subscriber may include the current location of the subscriber and whether or not the subscriber's handset is on or off. Another entity or application may subscribe to the presentity by sending a subscribe message to a presence server. The presence server may notify the subscribing entity of the initial presence status of the presentity and of changes in presence status of the presentity.
In some conventional networks that use presence protocols, a subscriber is required to have a general packet radio service (GPRS) handset with a presence client running on the handset in order for the presence information for the subscriber to be updated in the presence server database. For example, when a subscriber with a GPRS handset activates his or her handset in a new location area, the presence client on the subscriber's handset may automatically send a message to the presence database indicating that the subscriber is located in a particular area and that the subscriber's handset is activated.
Requiring that each subscriber have a presence client running on his or her handset in order for presence information to be collected prevents the development of universal-applicable applications that rely on presence information. For example, not all subscribers have GPRS handsets, not to mention GPRS handsets with presence clients. Accordingly, applications, such as SMS, push-to-talk, instant messaging, and conference calling, that rely on presence information are limited to subscribers with specialized communications equipment. Stated differently, because presence information is not available regarding all types of subscribers, including subscribers without GPRS handsets, the applicability of applications that rely on presence information is limited.
Another problem with current presence implementations is that presence information is only maintained for subscribers who are currently subscribed to by other entities. If a subscriber is not currently subscribed to, presence information may not be stored in a presence server database for that subscriber. As a result, when a subscriber becomes subscribed to, there may be delay between the time that presence information is obtained and delivered to the subscribing entity.
Accordingly, in light of these difficulties associated with conventional presence implementations, there exists a need for improved methods, systems, and computer program products for providing presence gateway functionality in a telecommunications network.